Prevalence and Clinical Profi le of Severe Acute Respiratory Syndrome Coronavirus 2 Infection Among Farmworkers, California, USA, June–November 2020

Joseph A. Lewnard; Ana M. Mora; Oguchi Nkwocha; Katherine Kogut; Stephen A. Rauch; Norma Morga; Samantha Hernandez; Marcus P. Wong; Karen Huen; Kristin Andrejko; Nicholas P. Jewell; Kimberly L. Parra; Nina Holland; Eva Harris; Maximiliano Cuevas; Brenda Eskenazi


Emerging Infectious Diseases. 2021;27(5):1330-1342. 

In This Article

Abstract and Introduction


During the ongoing coronavirus disease (COVID-19) pandemic, farmworkers in the United States are considered essential personnel and continue in-person work. We conducted prospective surveillance for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and antibody prevalence among farmworkers in Salinas Valley, California, during June 15–November 30, 2020. We observed 22.1% (1,514/6,864) positivity for SARS-CoV-2 infection among farmworkers compared with 17.2% (1,255/7,305) among other adults from the same communities (risk ratio 1.29, 95% CI 1.20–1.37). In a nested study enrolling 1,115 farmworkers, prevalence of current infection was 27.7% among farmworkers reporting ≥1 COVID-19 symptom and 7.2% among farmworkers without symptoms (adjusted odds ratio 4.16, 95% CI 2.85–6.06). Prevalence of SARS-CoV-2 antibodies increased from 10.5% (95% CI 6.0%–18.4%) during July 16–August 31 to 21.2% (95% CI 16.6%–27.4%) during November 1–30. High SARS-CoV-2 infection prevalence among farmworkers underscores the need for vaccination and other preventive interventions.


In response to the ongoing coronavirus disease (COVID-19) pandemic, the United States and other countries have implemented broad interventions to mitigate community transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).[1] Workers in food supply and other industries deemed essential to continuity of public health and safety have continued in-person work.[2] COVID-19 outbreaks have been reported among various essential workforce groups, including employees in food processing facilities,[3,4] but studies prospectively assessing risk for infection among essential workers involved in food production are lacking.

Agriculture and related food production industries comprise one of the lowest-paid sectors of the US economy; 29% of full-time workers earn an annual individual income of <$12,760 or $26,200 for a family of 4.[5] Agriculture in particular draws on a predominantly Latino immigrant workforce,[6] who work longer hours, receive lower wages, and experience higher levels of household poverty than their US-born counterparts.[7] Among immigrant farmworkers, ≈54% are undocumented and thus have reduced access to federal benefits under the Coronavirus Aid, Relief, and Economic Security Act.[8] Working conditions, poverty, and immigration status have compounded legal and economic challenges faced by farmworkers during the COVID-19 pandemic.[9,10]

We initiated surveillance of SARS-CoV-2 infection among farmworkers in Salinas Valley, California, to monitor the COVID-19 epidemic. We previously described impacts of the pandemic on economic well-being, mental health, and food insecurity within this population (A.M. Mora, unpub. data, Here, we report on the prevalence of SARS-CoV-2 infection among farmworkers tested during June–November 2020 and on symptoms and antibody responses within a subset of farmworkers enrolled in a cross-sectional study.